Keysight Technologies FieldFox A Series, User Manual

Page: 275 / 756

Keysight N9927-90001 User’s Guide 275
IQ Analyzer (IQA) – Option 351 (CPU2 Only)
I/Q Analyzer (IQA) Mode Settings
— Then RF Atten Auto Man .
— Auto RF Attenuation is set by adjusting the input power level. As the
acquisition is lowered, for example from –10 dBm to –30 dBm, the FieldFox
assumes that you are looking at low-level signals. The RF Attenuation value
is automatically lowered in 5 dB steps to allow low-level signals to be
viewed.
— Man RF Attenuation is set manually. The default Attenuation setting is
10 dB. Enter a value between 0 to 30 dB in 5 dB steps using the numeric
keypad, the
arrows, or the rotary knob. Then press Enter
#Atten xx dB is shown at the top of the screen. (#) means manual setting.
(Default: 10 dB, minimum: 0 dB, maximum: 30 dB.)
Preamplifier Control (Opt 235)
When very low-level signals are analyzed, an internal preamplifier can be used
to boost the signal level by approximately 18 to 22 dB. The gain of the preamp
is NOT adjustable. The displayed signal level is automatically adjusted for the
increase in system gain.
How to control the Preamp
By default, the preamp is OFF.
— Press Scale/Amptd .
— Then More
— Then Preamp Off The displayed setting is the current setting. When ON, PA
is shown to the left of the graticules on the display (default: OFF). When
OFF, nothing is displayed in the left graticules.
When Auto is selected, the preamp setting is determined by the RF
attenuation and to the input power level. When the input power level
reaches a certain value, the preamp is turned on and PA is shown to the left
of the graticules on the display.